The newest feature for Ubuntu users in the 11.04 release is Unity, the new UI for the desktop. Other features include a global menu, integrated dashes and touch screen support. A detailed list of changes can be found in the release notes

“This release breaks new ground for Ubuntu by offering users a PC experience that is stylish and efficient,” said Jane Silber, CEO of Canonical. “With this release Ubuntu will recruit an entirely new wave of users to free software. Ubuntu 11.04 is a high watermark for what has been achieved with open-source technologies for the everyday computer user.”